JP4988420B2 - Lighting device - Google Patents

Description

  The present invention relates to an illumination device including an optical filter capable of adjusting the color temperature of light.

  The color temperature of light is known to affect the biological rhythm and arousal level of humans. For example, light with low color temperature has a relaxation effect, while light with high color temperature It has the effect of increasing the arousal level. In recent years, focusing on the effect of the color temperature of light on human biological rhythms and the like, it is possible to obtain a comfortable illumination environment according to personal preference, environment, time, etc. by changing the color temperature of illumination light. There has been proposed an illumination device as described above.

  As such an illuminating device, an illuminating device including an optical filter that controls the color temperature of light by absorbing light of a specific wavelength out of light emitted from a light source and not transmitting the light is known. (For example, refer to Patent Document 1). In this type of lighting device, an optical filter provided in a lighting fixture has a liquid crystal cell containing dichroic dyes having different absorption spectral characteristics. When a voltage is applied to the liquid crystal cell, In response, the molecular arrangement of the dichroic dye contained in the liquid crystal changes to control the color temperature of the light transmitted through the optical filter.

Moreover, the illuminating device which can adjust the color temperature of light may be used as stage lighting, such as a stage. In such an illuminating device, a light output discharge lamp may be used as the light source, and in order to prevent the dichroic dye from changing with time due to ultraviolet light contained in the light emitted from the discharge lamp, An illumination device including an ultraviolet absorption filter between an optical filter is known (see, for example, Patent Document 2).
JP 2000-89188 A JP 2004-61828 A

  However, azo or anthraquinone dichroic dyes, which are known as typical dichroic dyes, have low light resistance. May lose the light absorption characteristics. For this reason, as shown in Patent Document 1 and Patent Document 2, in the illumination device using these dichroic dyes, the irradiation light may not be controlled to a desired color temperature in the long term.

  The present invention solves the above-described problem, and provides an illuminating device including an optical filter that can suppress deterioration over time of a dichroic dye and can stably adjust the color temperature of irradiation light over a long period of time. The purpose is to provide.

In order to solve the above problems, the invention of claim 1 is directed to an optical filter having a liquid crystal cell in which liquid crystals containing dichroic dyes having different absorption spectral characteristics are sandwiched between transparent substrates with transparent electrodes, a light source, the a lighting apparatus having an ultraviolet-absorbing filter provided, the between the optical filter and the light source, the dichroic dye, Ri consists fluorescent benzothiadiazole dyes, the liquid crystal is a hindered amine light It contains a stabilizer .

According to the first aspect of the present invention, since the fluorescent benzothiadiazole dye is used as the dichroic dye, the exposure to the lamp light is greater than when a general-purpose dichroic dye such as an azo dye or an anthraquinone dye is used. It is possible to effectively suppress the fading over time of the dichroic dye due to. Further, when a fluorescent benzothiadiazole dichroic dye and a hindered amine light stabilizer are combined, it is possible to further suppress the fading of the dichroic dye over time due to light exposure from a light source. Thereby, the light absorption characteristic of the dichroic dye is maintained for a long time, and the lighting device can control the color temperature of the irradiation light stably.

  The lighting fixture which concerns on one Embodiment of this invention is demonstrated with reference to FIG. The illumination device 1 includes a light source 2, an optical filter 3 disposed in the light emission direction of the light source 2, and an ultraviolet absorption filter 4 disposed on the light incident surface of the optical filter 3. In addition, the illumination device 1 appropriately includes a reflecting member 5 for reflecting the emitted light from the light source 2 in the direction of the optical filter 3. The light source 2, the optical filter 3, the ultraviolet absorption filter 4, and the reflection member 5 are accommodated in a housing 6 having an opening in the light emission direction. The light source 2 is connected to the light source power supply unit 7, and the optical filter 3 is connected to the filter control power supply unit 8.

  The light L <b> 1 emitted from the light source 2 is reflected directly or by the reflecting member 5, passes through the ultraviolet absorption filter 4 and the optical filter 3 provided in the opening of the housing 6, and is emitted outside the illumination device 1. The ultraviolet absorbing filter 4 may be disposed not only on the light incident surface of the optical filter 3 but also on the light emitting surface side. Thereby, the optical filter 3 can be protected from other illumination devices and the like.

  The light source 2 is a general-purpose light source, and FIG. 1 shows an example using a fluorescent lamp. However, the light source 2 may be an incandescent lamp, a high-intensity discharge lamp, or the like, and preferably has a flat emission spectral characteristic. Is used.

  The optical filter 3 controls the transmission of light of a specific wavelength out of the light L1 incident from the light source 2 in accordance with the power supply from the filter control power supply unit 8, thereby adjusting the color temperature of the light L2 transmitted through the optical filter 3. Change. A specific configuration of the optical filter 3 will be described later.

  The ultraviolet absorption filter 4 is a thin plate made of a translucent resin containing an ultraviolet absorber, and preferably absorbs light (ultraviolet light) having a wavelength of about 410 nm or less from the light L1 incident from the light source 2. The optical filter 3 is protected from ultraviolet rays. As an ultraviolet absorber, what contains at least 1 sort (s) among 2-hydroxy-benzophenone, 2- (2'-hydroxyphenyl) benzotriazole, or these derivatives is used, for example. In this embodiment, a general-purpose ultraviolet absorption filter that cuts light with a wavelength of about 360 nm or less by about 100% may be used, but it is desirable to use an ultraviolet absorption filter that cuts light with a wavelength of about 410 nm or less.

  An ultraviolet absorption filter that cuts off light having a wavelength of about 410 nm or less uses acrylic resin (trade name: VH001, manufactured by Mitsubishi Rayon) as a translucent resin material, and 2 TINUVIN 326 manufactured by Ciba Special Chemicals is used as the ultraviolet absorber for this resin material. %, And a general-purpose molding method such as extrusion molding, injection molding or cell cast molding is used. As the ultraviolet absorber, the above-mentioned 2-hydroxy-benzophenone, 2- (2'-hydroxyphenyl) benzotriazole or a derivative thereof is used. For example, TINUVIN327, TINUVIN3278 manufactured by Ciba Special Chemicals may be used.

  The reflecting member 5 is a general-purpose optical member, and for example, a resin structure formed in a bowl shape is vapor-deposited with high light reflectance aluminum or the like. Further, the reflecting member 5 may be configured such that the inner surface of the housing 6 is formed in a shape that exhibits desired optical characteristics and is subjected to a surface treatment such as aluminum vapor deposition.

  The housing 6 is a substantially cylindrical structural material having one opened and the other closed. Since the inside of the housing 6 may be exposed to a high temperature due to heat radiated from the light source 2, the housing 6 is formed of a metal material or a resin material having excellent heat resistance and durability.

  The light source power supply unit 7 receives power supplied from the commercial power source AC, converts it into a predetermined voltage according to the type of the light source 2, and supplies current to the light source 2. For example, when the light source 2 is a fluorescent lamp or the like, an appropriate circuit such as an inverter circuit 71 as shown in FIG. 1 is provided.

  The filter control power supply unit 8 uses a power supply that can receive a toning signal output by a user operation, etc., control an appropriate voltage corresponding to the toning signal, and output it to the optical filter 3. A detection circuit and a control circuit 81 that detect a signal and control an appropriate voltage according to the detected signal are provided.

  Next, a specific configuration of the optical filter 3 will be described with reference to FIG. In addition, in FIG. 2, description of the light source 2 and the light source electric power feeding part 7 is abbreviate | omitted. The optical filter 3 has a liquid crystal cell 35 in which a liquid crystal material 32 containing dichroic dyes 31 having different absorption spectral characteristics is sandwiched between transparent substrates 34 with transparent electrodes 33. The transparent substrate 34 is fixed by a sealing material 36. The transparent electrode 33 is connected to the filter control power supply unit 8 and is applied with an AC or DC drive voltage. Although FIG. 1 and FIG. 2 described above show the optical filter 3 having one liquid crystal cell 35, a plurality of liquid crystal cells 35 may be provided.

  The dichroic dye 31 has an absorption peak due to a unique molecular structure, and absorption spectral characteristics continuously increase from a long wavelength range to a short wavelength range, or absorption from a short wavelength range to a long wavelength range. Some spectral characteristics continuously increase. The absorption spectral characteristic refers to the light absorption characteristic for each wavelength of each substance. Common dichroic dyes include azo dyes, anthraquinone dyes, and the like. In this embodiment, assuming that they are exposed to the light L1 emitted from the light source 2 for a long period of time, the color fading is assumed. Fluorescent benzothiadiazole-based dichroic dyes are used with a small amount. The synthesis procedure and synthesis route of the fluorescent benzothiadiazole-based dichroic dye will be described later.

  A general-purpose thermotropic liquid crystal is used as the liquid crystal material 32. In the present embodiment, any of a nematic liquid crystal, a cholesteric liquid crystal, and a smectic liquid crystal may be used, but a nematic liquid crystal capable of obtaining a high-speed response is preferable. Note that a ferroelectric liquid crystal which is a kind of smectic liquid crystal may be used. The transparent electrode 33 applies an arbitrary voltage for adjusting its orientation to the liquid crystal material 32, and for example, an indium tin-based oxide is used. A general-purpose glass substrate is used for the transparent substrate 34.

  The liquid crystal material 32 is added with a light stabilizer 37 that receives excitation energy from the light-absorbing substance and suppresses deterioration of the light-absorbing substance. The light stabilizer 37 used in the present embodiment is a hindered amine light stabilizer, for example, CHIMASSORB 2020 FDL manufactured by Ciba Specialty Chemicals.

  Examples of the fluorescent benzothiadiazole dichroic dye used in the optical filter 3 of the present embodiment include 4,7-Di (2-thienyl) -2,1,3-benzothiadiazole and 4,7-Bis (5 -phenylthiophen-2-yl) -2,1,3-benzothiadiazole is used. The following are benzothiadiazole dichroic dyes 4,7-Di (2-thienyl) -2,1,3-benzothiadiazole and 4,7-Bis (5-phenylthiophen-2-yl) -2,1,3- The synthesis procedure of benzothiadiazole and its route will be described with reference to FIG. First, 4,7-Di (2-thienyl) -2,1,3-benzothiadiazole (target product (I)) is synthesized. Subsequently, after 4,7-Di (2-thienyl) -2,1,3-benzothiadiazole was converted to 4,7-Di (5-bromothiophen-2-y) -2,1,3-benzothiadiazole, 4 , 7-Bis (5-phenylthiophen-2-yl) -2,1,3-benzothiadiazole (target product (II)). The details are shown below.

<Synthesis of 4,7-Di (2-thienyl) -2,1,3-benzothiadiazole (target product (I))>
2-thiophene boron in a mixture of 4,7-dibromo-2,1,3-benzothiadiazole (2.95 g), tetrakistriphenylphosphine palladium (1.00 g), and benzene (100 mL) at 60 ° C under an argon atmosphere After adding an acid (4.05 g) solution in ethanol (25 mL) and 2M aqueous sodium carbonate (50 mL), the mixture was heated at 85 ° C. for 15 h. The reaction solution was concentrated under reduced pressure to remove benzene and extracted with dichloromethane. The extract was washed with water, dried over magnesium sulfate, and the solid obtained by distilling off the solvent under reduced pressure was recrystallized from hexane to give the desired product 4,7-Di (2-thienyl) -2,1 as red needle crystals. , 3-benzothiadiazole (target product (I)) was obtained.

<Synthesis of 4,7-Bis (5-phenylthiophen-2-yl) -2,1,3-benzothiadiazole (target product (II))>
Stir the chloroform solution (100 mL) of 4,7-Di (2-thienyl) -2,1,3-benzothiadiazole (100 mg) and NBS (125 mg) synthesized by the above method at room temperature under argon atmosphere for 48 hours. did. The precipitate was collected by filtration and washed with water, methanol, and chloroform to give the desired product 4,7-Di (5-bromothiophen-2-y) -2,1,3-benzothiadiazole as a red powder. Subsequently, at 60 ° C. under an argon atmosphere, the above 4,7-Di (5-bromothiophen-2-y) -2,1,3-benzothiadiazole (229 mg), tetrakistriphenylphosphine palladium (12 mg), benzene ( 16 mL) was added a solution of 4-phenylboronic acid (183 mg) in ethanol (4 mL) and 2M aqueous sodium carbonate (8 mL), and the mixture was heated at 85 ° C. for 12 hours. The reaction mixture was poured into water (100 mL) and extracted with chloroform. The extract was dried over magnesium sulfate, and the solid obtained by evaporating the solvent under reduced pressure was separated by column chromatography (silica gel (Wako Ggel C-300), hexane / chloroform = 1/1 (v / v), The desired product 4,7-Bis (5-phenylthiophen-2-yl) -2,1,3-benzothiadiazole (target product (II)) was obtained as a red powder.

  Next, the operation of the optical filter 3 configured as described above in the present embodiment will be described. When no voltage is applied to the transparent electrode 33 of the liquid crystal cell 35, the liquid crystal material 32 and the dichroic dye 31 having an elongated molecular structure are aligned in parallel (homogeneous alignment) with respect to the transparent substrate 34. Strongly absorbs polarized light oscillating in the long axis direction of the functional dye 31 (Heilmeier guest-host operation). Therefore, for example, the liquid crystal cell 35 including the dichroic dye 31 having the absorption spectral characteristic for the short wavelength component increases the color temperature of the transmitted light, while the dichroic dye 31 having the absorption spectral characteristic for the long wavelength component. The included liquid crystal cell 35 reduces the color temperature of the transmitted light.

  On the other hand, when a sufficient voltage is applied to the transparent electrode 33 of the liquid crystal cell 35, the liquid crystal material 32 having a long and narrow molecular structure and the dichroic dye 31 are reoriented in the electric field direction and rise perpendicularly to the transparent substrate 34. . Therefore, the absorption of the short wavelength component and the long wavelength component by the dichroic dye 31 is reduced, the transmission spectral characteristic of the liquid crystal cell 35 becomes flat, and the color temperature of the light transmitted through the liquid crystal cell 35 does not change.

  Thus, by appropriately controlling the voltage applied to the liquid crystal cell 35 including the dichroic dyes 31 having different absorption spectral characteristics, the transmission spectral characteristics of the liquid crystal cell 35 continuously change. Therefore, the optical filter 3 can control the transmission spectral characteristic in an analog manner by changing the voltage to be applied, and absorbs and emits light of a specific wavelength out of the light L1 incident from the light source 2. In addition, the illumination light L2 having a controlled color temperature can be emitted. Moreover, by providing this optical filter 3, the illuminating device 1 of this embodiment can emit the illumination light in which the color temperature of light is controlled in a wide range and continuously.

  Moreover, the illuminating device 1 of the present embodiment uses a dichroic dye 31 that is a fluorescent benzothiadiazole-based dichroic dye with less fading as the dichroic dye 31, so that the dichroic dye by ultraviolet rays irradiated from the light source 2 It is possible to effectively suppress the temporal deterioration of 31 and thus improve the light resistance of the optical filter 3 and to adjust the color temperature of the light emitted from the light source 2 stably over a long period of time.

  Hereinafter, Examples 1 to 3 and Comparative Examples 1 to 4 in the illumination device 1 of the present embodiment will be described with respect to the measurement results of the light transmission characteristics of the ultraviolet absorption filter 4 and the temporal change of the dichroic dye 31.

<Example 1>
As a liquid crystal material 32, a product name: JC-1069RB manufactured by Chisso Corporation is used, and a fluorescent dichroic dye 4,7-Di (2-thienyl) -2,1,3-benzothiadiazole is used as the dichroic dye 31. After 0.5 wt% of the dichroic dye 31 is dissolved in the liquid crystal material 32 and injected into a glass liquid crystal cell 35 (manufactured by HC Corporation) having a substrate interval of 7 μm, an ultraviolet curable sealing material is used as the sealing material 36. (The product made by HC Corporation, brand name: UV-RESIN LC610) was sealed. Further, as shown in FIG. 4, an ultraviolet absorption filter 4 that does not transmit substantially 100% of light having a wavelength of about 410 nm or less is disposed on the light incident surface and the light emitting surface of the optical filter 3. As the ultraviolet absorbing filter 4, an acrylic resin (trade name: VH001, manufactured by Mitsubishi Rayon) to which 2% of TINUVIN 326 manufactured by Ciba Special Chemicals was added as an ultraviolet absorber was used. The light transmission characteristics of the ultraviolet absorption filter 4 used here are shown in FIG.

<Example 2>
The dichroic dye 31 was prepared in the same manner as in Example 1 except that the fluorescent dichroic dye 4,7-Bis (5-phenylthiopen-2-yl) -2,1,3-benzothiadiazole was used. It was.

<Example 3>
The hindered amine light stabilizer (manufactured by Sivas Specialty Chemicals, trade name: CHIMASSORB 2020 FDL) was produced in the same manner as in Example 1 except that 0.5% by weight was melted with respect to the liquid crystal material 32.

<Comparative Example 1>
Except for using a dichroic dye (trade name: G-205, manufactured by Hayashibara Biochemical Laboratories) and not having an ultraviolet absorption filter 4 that does not transmit light having a wavelength of about 410 nm or less, about 100%. It was produced in the same manner as in Example 1.

<Comparative example 2>
Light having a wavelength of about 360 nm or less was used instead of the dichroic dye manufactured by Hayashibara Biochemical Laboratories, trade name G-205, and the ultraviolet absorption filter 4 that does not transmit substantially 100% of light having a wavelength of about 410 nm or less. Was produced in the same manner as Comparative Example 1 except that an ultraviolet absorption filter 4 made of an acrylic resin that did not transmit substantially 100% of the resin was provided. The ultraviolet absorption filter 4 was made of acrylic resin (trade name: VH001, manufactured by Mitsubishi Rayon Co., Ltd.) with 0.005% of TINUVIN324 manufactured by Ciba Special Chemicals. The light transmission characteristics of the ultraviolet absorption filter 4 used here are shown in FIG.

<Comparative Example 3>
It was produced in the same manner as in Example 1 except that Hayashibara Biochemical Laboratories product name G-205 was used as the dichroic dye.

<Comparative example 4>
A hindered amine light stabilizer (manufactured by Ciba Specialty Chemicals, trade name CHIMASSORB 2020 FDL) was prepared in the same manner as in Comparative Example 3 except that 0.5% by weight was melted with respect to the liquid crystal material 32.

<Light resistance test A>
The transmission spectrum of the dichroic dye is measured in a wavelength range of approximately 300 to 800 nm using a self-recording spectrophotometer (trade name U-4000, manufactured by Hitachi, Ltd.), and the transmittance in the initial state of the colored state is applied with no voltage applied. Asked. After that, after installing a non-voltage-applied (colored) liquid crystal cell at a distance of 200 mm from the mercury lamp in a 60 ° C hot-air circulating thermostat equipped with a 400 W mercury lamp (made by Matsushita Electric Industrial Co., Ltd., product name H400), the mercury lamp is turned on. Lamp light was irradiated. After 4 weeks, a transmission spectrum in the wavelength range of 300 to 800 nm was measured. Of the above-mentioned Examples and Comparative Examples, the transmission spectra before and after the light resistance test A in Comparative Example 1 and Examples 1 and 2 are shown in FIGS. 7, 8A, and 8B, respectively. In addition, at the absorption peak wavelength of 480 nm of the dichroic dye, an increase value of the transmittance after the test with respect to the transmittance in the initial state is obtained, and when the increase in the transmittance is less than 1%, ◎, % Is less than 5%, △ is when the increase in transmittance is 5% or more and less than 10%, and x is when the increase in transmittance is more than 10%. The determination results are shown in Table 1 below.

  As is apparent from the results of the light resistance test A performed on Example 1 and Comparative Examples 1 and 2, according to this embodiment, the ultraviolet absorption filter does not transmit substantially 100% of light having a wavelength of about 410 nm or less. The time-dependent alteration of the dichroic dye 31 can be effectively suppressed when not using the ultraviolet absorption filter or when using a general-purpose ultraviolet absorption filter. Moreover, since a general-purpose substance is used as the ultraviolet absorber, the production cost of the entire lighting device can be reduced. In addition, by using a fluorescent benzothiadiazole system for the dichroic dye 31, fading of the dichroic dye over time is significantly suppressed.

<Light resistance test B>
The transmission spectrum of the dichroic dye is measured in a wavelength range of 300 to 800 nm using a self-recording spectrophotometer (manufactured by Hitachi, trade name U-4000), and the transmittance in the initial state of the colored state is measured with no voltage applied. Asked. Thereafter, a light resistance test was carried out for 24 hours in a metal weather light resistance test tank manufactured by Daipla Intes. (Light source: metal halide lamp, lamp radiation intensity of 80 μw / cm ² , in a hot-air circulating thermostat, internal temperature: 90 ° C., distance between lamp and sample: 200 mm). After 24 hours, a transmission spectrum in the wavelength range of 300 to 800 nm was measured. Of the above-mentioned Examples and Comparative Examples, the transmission spectra before and after the light resistance test B in Examples 1 and 2 are shown in FIGS. Further, the increase in the reflectance after the test with respect to the reflectance in the initial state at the absorption peak wavelength of 480 nm of the dichroic dye was determined, and when the increase in transmittance was less than 1%, the increase in transmittance was 1% or more 5 When the ratio is less than%, the fading performance is determined as ◯, when the increase in transmittance is 5% or more and less than 10%, and when the increase in transmittance exceeds 10%, the fading performance is determined. It is shown in Table 2 below.

  As is clear from the test results of the light resistance test B in Example 1 and Example 2, when a fluorescent benzothiadiazole dichroic dye was used, a hindered amine light stabilizer was added to a general-purpose azo dye. Also shows excellent light resistance. When the fluorescent benzothiadiazole dichroic dye and the hindered amine light stabilizer are combined, the fading of the dichroic dye over time due to light exposure from the light source 2 can be further suppressed.

  In the illumination device 1 of the present embodiment configured as described above, the fluorescent benzothiadiazole dye used as the dichroic dye 31 is given to the dye molecules because the absorbed energy is released not by heat but by fluorescence. It is considered that the damage is reduced, and it is possible to effectively suppress the fading of the dichroic dye over time due to light exposure from the light source, compared to the case of using a general-purpose dichroic dye such as an azo type or an anthraquinone type. It is considered a thing.

  The present invention is not limited to the configuration of the above embodiment, and various modifications can be made. Moreover, the optical filter 3 using the fluorescent benzothiadiazole dye synthesized as described above as a dichroic dye has various electric configurations configured to control the color temperature of light emitted from the light source. Adaptable to equipment.

The fragmentary sectional view which shows the structure of the illuminating device which concerns on one Embodiment of this invention. The cross-sectional block diagram of the optical filter of the illumination device. The figure which shows the synthetic pathway of a fluorescent dichroic dye. The cross-sectional block diagram of the optical filter of the illumination device provided with the ultraviolet absorption filter. The figure which shows the spectral transmission characteristic of the ultraviolet absorption filter which cuts about 100% of light with a wavelength of about 410 nm or less. The figure which shows the spectral transmission characteristic of the ultraviolet absorption filter which cuts about 100% of light with a wavelength of about 360 nm or less. The figure which shows the displacement of the transmittance | permeability in the pigment | dye absorption peak wavelength position before and after the light resistance test A of the comparative example 1. FIG. (A) is the figure of Example 1, (b) is a figure which shows the displacement of the transmittance | permeability in the dye absorption peak wavelength position before and behind the light resistance test A of Example 2. FIG. (A) is the figure of Example 1, (b) is a figure which shows the displacement of the transmittance | permeability in the dye absorption peak wavelength position before and behind the light resistance test B of Example 2. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Illuminating device 2 Light source 3 Optical filter 31 Dichroic dye 32 Liquid crystal material 33 Transparent electrode 34 Transparent substrate 35 Liquid crystal cell 4 Ultraviolet absorption filter

Claims (1)

An optical filter having a liquid crystal cell in which liquid crystals containing dichroic dyes having different absorption spectral characteristics are sandwiched between transparent substrates with transparent electrodes, a light source, and an ultraviolet absorption filter provided between the optical filter and the light source And a lighting device comprising:
The dichroic dye, Ri consists fluorescent benzothiadiazole dyes,
The illuminating device , wherein the liquid crystal contains a hindered amine light stabilizer .

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